Abstract

Tilted fault-blocks in the North Sea show varying degrees of erosion. Such footwall erosion is predicted by the domino model of extension, in which rigid fault-blocks rotate as extension proceeds. Profiles of three North Sea fields (Snorre, Brent and Heather) are analysed to estimate the amount of uplift that accompanied Late Jurassic normal faulting, and these estimates are compared with the footwall uplift predicted by the domino model. Agreement between observed and predicted uplift is excellent, varying from >1 km at Snorre to c. 100 m at Heather. For a given amount of extension, large fault-blocks tend to be bounded by large faults and to show a greater degree of erosion.

The Brent Province of the northern North Sea is an area of prolific hydrocarbon discoveries. Almost all of the major oil-fields occur in tilted fault-blocks which were formed by Late Jurassic extension and subsequently buried by Cretaceous-Tertiary thermal subsidence (Badley et al. 1988; Marsden et al. 1990). The crests of the tilted blocks are typically eroded or degraded, with varying amounts of Middle-Lower Jurassic and Upper Triassic section removed. This footwall erosion is commonly ascribed in the literature to pre-rifting doming (Ziegler 1982), heterogeneous stretching (Coward 1986), local transpression (Beach 1985) or even regional compression (Frost 1987). The purpose of this paper is to show that the uplift and degradation is a direct consequence of the Late Jurassic normal faulting and fault-block rotation. The degree of uplift is related in a simple way to the size (across strike) of

Purchase access

You may purchase access to this article. This will require you to create an account if you don't already have one.

LIBRARY USERS

Log in through your institution

You may be able to gain access using your login credentials for your institution. Contact your library if you do not have a username and password.

If your organization uses OpenAthens, you can log in using your OpenAthens username and password. To check if your institution is supported, please see this list. Contact your library for more details.